The vacuum equipment is designed to evacuate the chamber to the required vacuum level within a specified time. This creates optimal conditions for the integral leak test with SF6.

With the assistance of a suitable conveyor vehicle, correspondingly specified test specimens with a volume of more than 500 litres are introduced into the vacuum chamber.

The leak test system consists of a vacuum chamber with automatic door mechanics, vacuum pumping stations and all necessary valves as well as measuring cells for controlling the test process.

Test Procedure

A test specimen (e. g. GIS, measuring transducers or similar) is placed by the system operator in front of the chamber on a frame with heavy-duty rollers, and is passed into the vacuum chamber. It is also possible to place several smaller test specimens in the chamber at the same time. The limit is set by the chamber size.

The vacuum chamber is connected to the vacuum pumping stations, which are dimensioned according to the chamber volume, via appropriate pipelines and generate the necessary vacuum at two remote vacuum ports close to the floor. The test process is initiated by selecting a product-specific material number then pressing a start button. The chamber is closed and first evacuated to a selected pressure between 0.1 and 10 mbar. Subsequently, flooding takes place up to the required process pressure of approx. 10... 15 mbar.

The respective pressures are stored in the controller as variable parameters. The pressure inside the chamber is permanently monitored. If a preset threshold value is exceeded the error message "Coarse leak" is displayed. This is to avoid contamination of the vacuum chamber with SF6 in case of a leaking test piece. In the event of a leaking test piece, the process is terminated in a controlled manner, and flushing cycles are started.

After the coarse leakage test, the SF6 LASERCHECK P3:vac is connected to the chamber and the fine leakage test is carried out via the suction line to the SF6 leak detector. After the measuring time has elapsed, a pass/fail decision is made via a setpoint comparison and displayed accordingly. The chamber is then flooded to atmospheric pressure. A failed part must in addition be acknowledged by the worker. Finally, the chamber door is opened and the tested part can be removed from the chamber by a conveyor vehicle.